Android WebView: use the system ashmem.

Android WebView: use the system ashmem.

We are already pulling in the system ashmem via other system libraries,
so compiling a second copy into chrome causes linker issues. Use the
system version in Chromium as well when building WebView as part of the
Android build.

BUG=157326
Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=190771

[Torne, 2013-03-22 11:16:46]

Hi Paweł,

This CL doesn't work as-is; I was hoping you could suggest the best way to deal
with it. The problem is that the system ashmem header on android is not
<ashmem.h> but <cutils/ashmem.h> (it's in a separate library that isn't part of
libc), and so the generated shim header doesn't find it. It doesn't look like
there's a way to remap this in the shim header generator currently. What's the
best way to deal with this? Extend the header generator with an optional
argument?

Thanks for the shim generator, btw, it makes life much easier doing this kind of
change :)

[Paweł Hajdan Jr., 2013-03-22 17:52:47]

Yes, feel free to take
https://codereview.chromium.org/12224030/diff/7001/tools/generate_shim_header...
and adjust it if needed.

Glad to see it's useful!

[Torne, 2013-03-25 16:41:02]

Okay, I took that patch and that's sufficient to make this work; I can now link
with the system ashmem here. Does this look okay to you Paweł?

I haven't introduced a specific use_system_ashmem flag because I think this only
makes sense in the WebView build; ashmem is Android-specific and isn't part of
the NDK, so you can't really use it anywhere else, and we need to use it always
to avoid potential issues.

[Torne, 2013-03-25 16:41:54]

+brettw because third_party/ashmem has no specific owner
+benm for general webview review

[brettw, 2013-03-25 17:20:43]

Can we find a good owner for third_parth/ashmem? Or is it DEPSed in from
somewhere in Android?

[Torne, 2013-03-25 17:23:00]

On 2013/03/25 17:20:43, brettw wrote:
> Can we find a good owner for third_parth/ashmem? Or is it DEPSed in from
> somewhere in Android?

It's not using DEPS, it's copied here from the Android tree. It's just a very
tiny set of wrappers for syscalls. The actual code is unlikely to ever change.
So, I don't know who should own it.

[joth, 2013-03-25 17:29:07]

+digit, as resident expert in android system C APIs, would you be happy to
be an OWNER for third_party/ashmem, or can recommend someone?



On 25 March 2013 10:23, <torne@chromium.org> wrote:

> On 2013/03/25 17:20:43, brettw wrote:
>
>> Can we find a good owner for third_parth/ashmem? Or is it DEPSed in from
>> somewhere in Android?
>>
>
> It's not using DEPS, it's copied here from the Android tree. It's just a
> very
> tiny set of wrappers for syscalls. The actual code is unlikely to ever
> change.
> So, I don't know who should own it.
>
>
https://codereview.chromium.**org/12674026/<https://codereview.chromium.org/1...
>

[Paweł Hajdan Jr., 2013-03-25 17:46:54]

LGTM

Good to see the tools I've developed to help us be a good Open Source citizen
are useful for Android!

[Torne, 2013-03-25 17:48:15]

On 2013/03/25 17:46:54, Paweł Hajdan Jr. wrote:
> LGTM
> 
> Good to see the tools I've developed to help us be a good Open Source citizen
> are useful for Android!

Yes, for the Android WebView build we need to use system libraries where
possible to reduce ROM footprint and avoid ABI issues (as we will end up being
loaded into many processes that may already load those system libraries via
other dependencies).

[benm (inactive), 2013-03-25 18:41:26]

lgtm

[digit1, 2013-03-26 13:47:22]

lgtm

[digit1, 2013-03-26 13:56:45]

lgtm for my addition to OWNERS for third_party/ashmem. It'd be nice to have
brettw's approval as well.

[Torne, 2013-03-26 13:57:28]

Brett, I've added digit@chromium.org as an owner for ashmem as he's the Android
NDK expert.

[brettw, 2013-03-26 17:39:52]

thanks! LGTM

[commit-bot: I haz the power, 2013-03-26 18:10:59]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/torne@chromium.org/12674026/15002

[commit-bot: I haz the power, 2013-03-26 21:26:02]

Change committed as 190771